The application of chemicals to the ground in a farm field including fertilizer and weed spray require a ground marking system for the vehicle operator to observe guideline markings in making trips back and forth across the field to assure that the chemicals are uniformly applied to the ground. The marking is commonly provided through the use of foam being applied to the ground in a broken line as disclosed in U.S. Pat. No. 5,570,539 Nov. 5, 1996.
Typical foam marking equipment includes an air pressurized foam holding tank into which liquid foam and water are introduced. The problem is that the liquid foam will spew out of the fill opening onto the operator and the equipment when liquid foam is being introduced into the foam holding tank. The liquid foam may contain dyes which will leave discolored stains on the equipment. Thus, what is needed is a system for refilling the foam holding tank with liquid foam and water without foam being spread uncontrollably over the operator and equipment.